Polishing cloth



Patented July 9, 1946 POLISHING CLOTH V 7 John D. Morgan, South Orange, and Russell E.

Lowe, East Orange, N. J., assignors to. Cities Service Oil Company, New York, N. Y., acorporation of Pennsylvania No Drawing. ApplicationJanuary 2.6, 1945',

Serial No. 574,832

9 Claims. (01. 51-294) This invention relates to the cleaning of metals and more particularly to an improved polishing cloth for raising a high sheen on aluminum, stainless steel, copper, brass, silver, and other bright metal surfaces.

The principal object of the invention is to pro vide a soft, flannel-like rubbing cloth which contains all of the ingredients needed for'the removal of dirt, oxides, sulphides, and other discoloringmatter forming or collecting onmetal surfaces, and which is adapted to dry clean a metal article a d to bring up a highly polished native metal to best advantage.

It is a further object of the invention to provide a dry cleaning cloth in accordance with the foregoing which is generally suited to the cleaning and polishing of both precious and base metals, and which is particularly effective in cleaning and brightening aluminum surfaces of aircraft, stainless steel exteriors of railroad cars, and other metal surfaces which are so large that they do not lend themselves readily to treatment by conventional polishing methods.

Wehave'found that an excellent dry cleaning and polishing cloth can be prepared by impregnating a sheet of absorbent fabric with a mixture of the following ingredients, proportioned by weight:

. Per cent Oleic acid 4-11 Triethanolamine 1- 4 Magnesium oxide, light 29-60 Calcium carbonate, precipitated 15-45 Infusorial earth (Dicalite white filler) 10-30 The invention may be better understood by a consideration of the following example of the preparation of polishing cloths for usein the cleaning and brightening of, aluminum aircraft surfaces. As a first step, we prepared a polishing mixture in which the foregoing, ingredients were suspended and dissolved in a carrier of Stoddard solvent. In carrying out this step, we charged 500 cos. of Stoddard solvent into a colloid mill of. the circulating type, which was set surface that shows off the natural beautyof the for operation at a minimum workingv distance, 7

and then added 8 grams of. oleic acid, together with 40 grams of. magnesium oxide (light), 30 grams of precipitatedcalcium carbonate and 20 grams of infusorial earth. The mill, of course, acted to churn and thoroughly distribute the abrasive material and the oleic acid throughout. the Stoddard solvent vehicle. Triethanolamine was then added to the extent of 2 grams, andthe complete charge was milled for'about five minutes to insure uniform mixing and thorough distribution of all of the ingredients throughout the vehicle.

The batch of polishing material which was prepared in the foregoing manner was found to be sufiicient to impregnate four cloths each measuring about 18 by 28 inches. The sheet material employed-as abase cloth was ordinary Canton flannel, although we have found that almost any soft and absorbent fabric will serve equally well. These sheets were dipped successively into the reservoir of the mill, and allowed to stand for a long, enough period of time to become thoroughly soaked. At this point itshould be noted that the polishin mixture was kept. under activeagita- 'tion during the dipping process by continued operation of the; mill to. insure uniform distribution and to prevent the settling out of the abrasive grains. As each sheet .became thoroughly saturated with the Stoddard solvent and polishing ingredients, it was withdrawn from the reservoir, passed through a wringer to remove excess solvent which was allowed to flow back toth'emill, and was then hung to dry.

he Stoddard solvent, as has been indicated above, serves only as a vehicle for the polishing ingredients during the milling operation and during the impregnation of the cloths. Any small quantity of this material which remains in the cloth. following. the wringing operation quickly evaporates away when thecloths are hung to dry, leavingv them completely filled with the abrasive materials, triethanolamine, and oleic acid. Stoddard solvent was chosen as the vehicle primarily because of the fact that it evaporates fully with outleaving any heavy ends in the cloth and polishing mixture. It is also an advantageous material for this use because of its classification as a fsafety solvent, and its consequent low fire hazard. Those familiar with the art will readily recognize, however, that other solvents may be substituted for Stoddard solvent in the preparation of the polishing, mixture, and in the subsequent impregnation step.v

The finished cloths contain a mixture of three abrasive ingredients, each of which serves its own function in, cleaning and polishing the metal surfaces over which the cloth isrubbed. The magnesium oxide, light, is the finest grained abrasive in the mixture, its particlesbeing of a size which can be conveniently measured only in terms of microns. This material is an excellent polishing agent and serves particularly in bringused alone, however, the magnesium oxide is not coarse enough to remove dirt and other coarse matter without excessive rubbing. Infusorial earth, on the other hand, is a comparatively coarse-grained material and acts to strip dirt, oxides, and the like from metal surfaces with minimum rubbing effort. By itself, however, this material is not capable of bringing out the fine finish and high luster which is usually required of a polishing operation. The calcium carbonate is an abrasive of a size between that of the very fine magnesium oxide and the somewhat coarser infusorial earth. It acts both to speed the cleaning operation and also to insure the bringing out of a bright finish on the polished article. The exact proportions of these ingredients to the whole polishing mixture may of course be varied to attain difierent results. We have found, however, that the proportions set forth in the example give optimum results in the polishing of aluminum, brass, and copper, in terms of fast and effective removal of dirt and stains, and of a final surface of maximum brightness.

The oleic acid and triethanolamine ingredients of the mixture react to form a triethanolamine oleate which serves as a binder for the finely powdered abrasive materials in the finished cloth. We have found that about 6 per cent by weight of the oleate functions most effectively to hold the powdered ingredients in the cloth, and to prevent the excessive loss of abrasive material by powdering Any quantity greatly in excess of that amount, however, tends to make a Waxy cloth in which the triethanolamine coats the abrasive grains so heavily as to cause them to lose a great deal of their polishing effectiveness.

The triethanolamine oleate constituent of the finished cloth also serves as a powerful detergent. When the dry cloth is rubbed over a dirty metal surface, this material is highly effective in removing dirt and other coarse matter. The detergent action of the material can, of course, be materially increased by dampening the clotha procedure which is preferable in polishing small articles which can subsequently be washed without too much trouble. In the cleaning of large articles, however, the cloth is well adapted to be used dry, so that neither a preliminary nor a final washing operation is necessary to the securing of a clean and brightly polishedsurface.

In making up the polishing mixture, we prefer to employ a greater quantity of oleic acid than can react with the triethanolamine. The propertions of these ingredients in the example composition are such that approximately 4 per cent of free oleic acid is retained in the finished cloth. This free acid constituent is particularl effective when the cloth is used upon aluminum, where it seems to raise a higher finish on that metal than can be achieved by the use of abrasives and detergents alone. It is important, however, that the free oleic acid shall not comprise too great a proportion of the whole mixture, as we have found that cloths containing very much more than 4 per cent of the acid tend to leave a somewhat greasy and sticky coating on the metal on which finger marks and streaks stand out to mar the brightly polished surface.

Some adjustment may be made in the proportions of the ingredients which go into the polishing mixture, within the general limits heretofore given. We have found, however, that the example composition is particularly effective in the dry cleaning and polishing of aluminum, brass and copper surfaces, and as a polishing cloth 4 of general utility. Where special polishing problems arise, then some variations may be made, particularly in the relative amounts of abrasive ingredients, and in the amount of, free oleic acid which is retained in the finished mixture, all for the purpose of attaining specific desired polishing results.

Having described ur invention, what we claim as new is:

1. A cloth for cleaning and polishing metal surfaces comprising a soft and absorbent sheet impregnated with a polishing mixture consisting of from 5 to per cent by weight of oleic acid, from 1 to 4 per cent by weight of triethanolamine, from 2,0 to 60 per cent by weight of magnesium oxide (light), from to 45 percent by weight of precipitated calcium carbonate, and from 10 to 30 percent of infusorial earth.

2. A cloth for cleaning and polishing metal surfaces comprising a soft, absorbent fabric sheet containing a polishing mixture of from to 60 per cent by weight of magnesium oxide (light), from 45 to 15 per cent by weight of precipitated calcium carbonate, and from to 10 per cent by weight of infusorial earth, and the remainder of a mixture of about 2 per cent by weight of triethanolamine and about 8 percent by Weight of oleic acid.

3. A cloth for cleaning and polishing metal surfaces comprising of an absorbent sheet of fabric containing a polishing mixture of from about 20 to 60 per cent by weight of magnesium oxide (light) from about 45 to 15 percent by weight of precipitated calcium carbonate, from about 10 to 30 per cent by weight of infusorial earth, and about 10 per cent by weight of triethanolamine oleate and free oleic acid in such proportions that the triethanolamine oleate serves to bind the finely powdered abrasive ingredients to the sheet.

4. A cloth for cleaning and polishing metal surfaces consisting of a sheet of absorbent fabric containing about per cent by weight of magnesium oxide (light), about 30 per cent by weight of precipitated calcium carbonate, about 20 per cent by Weight of infusorial earth, and about 10 per cent by weight of a mixture of oleic acid and triethanolamine in such proportions as to form sufiicient triethanolamine oleate to bind the finely powdered abrasive ingredients to the sheet and to leave a minor percentage of free oleic acid.

5. A cloth for cleaning and polishing metal surfaces, consisting of a sheet of absorbent fabric containing about 40 per cent by weight of magnesium oxide (light), about 30 per cent by Weight of precipitated calcium carbonate, about 20 per cent by weight of infusorial earth, about 8 per cent by weight of oleic acid, and about 2 per cent by weight of triethanolamine.

6. A cloth for cleaning and polishing metal surfaces consisting of a sheet of absorbent fabric containing about 40 per cent by weight of magnesium oxide (light), about 30 per .cent by weight of precipitated calciumcarbonate, about 20 per cent by weight of infusorial earth, about 6 per cent by weight of triethanolamine oleate, and about 4 per cent by weight of free oleic acid.

'7. A cloth for dry cleaning and polishing aluminum surfaces, which consists of a sheet of Canton flannel impregnated with a mixture of about 40 per cent by weight of magnesium oxide (light), about 30 per cent by weight of precipitated calcium carbonate, and about 20 per cent by weight of infusorial earth, and about 10 per cent by weight of a mixture of oleic acid and triethanolamine in such proportions as to form enough triethanolamine oleate to act as a binder for the other ingredients.

8. A cloth for cleaning and polishing metals comprising a soft fabric sheet impregnated with a polishing mixture of abrasive powder, about 2 parts by weight of triethanolamine, and about 8 parts by weight of oleicacid, the resulting triethanolamine oleate serving as a binder for the abrasive powder and as a detergent in cleaning metal surfaces.

9. A cloth for cleaning and'lpolishing metal surfaces comprising a sheet of soft fabric impregnated with abrasive polishing powder, and a binder of triethanolamine oleate for holding said powder in said fabric, said triethanolamine oleate also serving as a detergent agent in cleaning metal surfaces.

JOHN D. MORGAN. RUSSELL E". LOWE. 

